Comb-like Copolymers Research Articles

Dissipative particle dynamics simulation study on complex structure transitions of vesicles formed by comb-like block copolymers

Vesicles are membrane-enclosed capsules that can store or transport substances. Their structures and the corresponding structural transitions are important to fulfill specific functions. Using dissipative particle dynamics method, we study the complex structure transitions of vesicles that are spontaneously formed by A 6( B 2) 3 type comb-like block copolymers. In the simulations, the interaction parameters between different components are tuned to mimic the variations of amphiphilicity of the block copolymers and the selectivity of the solvent which are experimentally tractable by, for example, a temperature quench. Complex vesicle structures are found in this research; their transitions, such as fission and reversal, are studied in detail with this dynamic simulation method. We find that the line tension plays a decisive role on the vesicle fission pathways. Moreover, the tube-like vesicles tend to transform to a special layered micelle structure, whereas the onion-shape vesicles tend to transform to reverse onion-shape vesicles when vesicle reversal takes place due to the variation of solvent selectivity.

Synthesis and Characterization of Comb-Like Copolymer Dispersant with Methoxy Poly (Ethylene Oxide) Side Chains

A series of comb-like copolymer with variation in poly(ethylene oxide) side chain length and anionic group content was synthesized successfully for detailed interfacial studies by free radical copolymerization of sodium acrylate with methoxy poly (ethylene oxide)-acrylate (MPEGAA) without any crosslinking reaction. MPEGAA were synthesized first by catalytic esterification of acrylic acid with methoxy poly (ethylene oxide) (MPEG) using dicyclohexyldimethylcarbodiimide and 4-dimethylaminopyridine as a catalyst. The degree of conversion in relation to MPEG was found to be close to 100%. The FT-IR, 1H-NMR and GPC show that the structure and molecular weights of target copolymers are consistent with the designed structure.

New Generation Amphoteric Comb-like Copolymer Superplasticizer and Its Properties

The incorporation of high performance superplasticizers in concrete is one of the most effective and economic technological methods for achieving sustainable development in the concrete industry. Conventional polyelectrolyte-type superplasticizers have some defects, e.g. poor dispersibility, large slump loss, increasing the shrinkage of concrete and pollution when being manufactured. Although the new generation of comb-like polycarboxylate superplasticizers has remarkable benefits in practice, it also has the shortcoming of low saturation dosage. In this study, based on adsorption-dispersion mechanism of dispersant and polyampholyte solution theory, a new class of amphoteric comb-like copolymer superplasticizer (PACP) was designed and synthesized. The effects of PACP on water reduction, setting, compressive strength, hydration and pore structure were investigated systematically. Results show that PACP can be dosed in small amounts to obtain a water reduction up to 45%. The addition of PACP also does not retard cement hydration and significantly increases the compressive strength of hardened concrete at early and ultimate stages. Moreover, PACP can further improve the rate of heat evolution, delays the time to reach the highest hydration temperature and refines the pore structure of hardened cement paste markedly, leading to decreases of porosity and average pore size.

Amphiphilic polymeric particles with core–shell nanostructures: emulsion-based syntheses and potential applications

The design and synthesis of amphiphilic nano- to micro-sized polymeric particles with core–shell nanostructures have attracted more and more attention because of their wide applicability in modern material science and their technological importance in the areas of colloid and interface science. Many synthetic strategies have been developed for the preparation of amphiphilic core–shell particles that consist of hydrophobic polymer cores and hydrophilic polymeric shells. In this review, we focus on emulsion-based approaches and properties of particles produced. These methods are: (1) grafting to functionalized particle that produces a corona-like particle, (2) grafting from reactive seed particle that produces a brush-like particle, (3) copolymerization of reactive macro-monomer with hydrophobic monomer that produces a corona-like particle, (4) emulsion polymerization in the presence of block or comb-like copolymer containing controlled free-radical moiety that produces a multi-layered particle, and (5) redox-initiated graft polymerization of vinyl monomer from a water-soluble polymer containing amino groups that produces a hairy-like particle. Potential applications of some of these particles in drug and gene deliveries, enzyme immobilization, colloidal nanocatalyst, chemical sensing, smart coating, and thermal laser imaging will be discussed.

Hierarchical synthesis of silver nanoparticles and wires by copolymer templates and visible light

Self-assembled silver wires in micro-meter scale were obtained from aqueous silver nitrate solution in the presence of a comb-like copolymer as the sole organic component. The requisite copolymer was easily prepared by the grafting poly(oxyethylene)-monoamine (POE-amine) onto poly(styrene-co-maleic anhydride) (SMA). Upon storage at ambient temperature with exposure to daylight, the aqueous AgNO(3)/SMA-POE solution gradually underwent a color changed from transparent pale-yellow to dark-violet over a period of hours, and after several months a solid precipitate was deposited. The formation process was monitored by ultraviolet-visible spectrometer, particle size analysis, scanning electron microscope, and transmission electron microscope. Silver wires were hierarchically formed by progressive transformation from the initial appearance of silver nanoparticles (ca. 10nm in diameter), followed by the intermediate rectangles (0.6-1.0μm in width and 0.4μm in length) in solution and ultimately the precipitates in micro-scale of silver wires at 1.6-6.4μm in diameter and 100-370μm in length. The progressive formation of the precipitated silver wires was accelerated by the exposure of visible light as a photo-reducing energy source. The micron-scale wires have a silver content over 97.4wt.% and a sheet resistance of 5.5×10(1)Ω/square.

Thermo-Responsive Association of Chitosan-graft-Poly(N-isopropylacrylamide) in Aqueous Solutions

A comb-like dual hydrophilic graft chitosan copolymer, chitosan-graft-poly(N-isopropylacrylamide) (CS-g-PNIPAM), was synthesized by means of atom transfer radical polymerization (ATRP) and click chemistry. The thermo-responsive association behavior of the copolymer in dilute aqueous solutions has been investigated by laser light scattering (LLS), zeta potential, and transmission electron microscopy (TEM). The core-shell structured micelles with the hydrophobic PNIAPM as a core and the hydrophilic CS as a shell were formed at low pH (<4) and high temperature (>32 degrees C), whereas the obtained micelles became large aggregates and precipitated in alkaline solutions (pH > 7). Additionally, the low critical solution temperature (LCST) phase transitions of dense copolymer solutions in the presence of salts (NaCl and NaI) and a cationic surfactant (dodecyltrimethylammonium bromide, DTAB) respectively were studied by micro differential scanning calorimetry (DSC) and UV turbidimetry. It was found that both salts (NaCl and NaI) and DATB could shift the LCST to lower or higher temperatures from a pure copolymer solution, depending on the beneath mechanisms.

Self-assembly of a series of random copolymers bearing amphiphilic side chains

A novel series of comb-like random copolymers were prepared by polymerization of amphiphilic macromonomers, 2-(acrylamido)-octane sulfonic acid (AMC 8S), 2-(acrylamido)-dodecane sulfonic acid (AMC 12S), and 2-(acrylamido)-hexadecane sulfonic acid (AMC 16S), with 2-(acrylamido)-2-methylpropanesulfonic acid (AMPS) respectively. The synthesis of the polymers with the same contents of amphiphilic units as side chains, but different chain length, enabled us to study the chain length dependence of their association in salt solution. Steady-state fluorescence measurements with pyrene as a polarity probe, quasielastic light scattering techniques (QELS) and transmission electron micrograph (TEM) were employed to investigate the associative properties of the system. The above investigations showed that all kinds of side chains begin to assemble at certain polymer concentrations and the critical aggregation concentration (CAC) decrease dramatically with the increase in the length and content of alkyl. An interesting phenomenon is that the assembly tends more favorably to occur among different molecules rather than within single molecule when the number of carbon atoms in the alkyl groups or the polymer concentration increases, leading to the formation of larger multimolecular micelle-like aggregate. The aim of the present work is to establish the fundamental preconditions of intramolecular and intermolecular association fashions for the polymers, which is useful for the exploitation of functional groups and contributes to the development of amphiphilic random polymers.

Self-assembly of pH-responsive and fluorescent comb-like amphiphilic copolymers in aqueous media

“Comb-like” graft copolymers, consisting of a poly((N-vinylcarbazole)-co-(4-vinylbenzyl chloride)) (P(NVK-co-VBC)) copolymer backbone from free radical polymerization and poly(((2-dimethylamino)ethyl methacrylate)-co-(tert-butyl acrylate)) (P(DMAEMA-co-tBA)) side chains from atom transfer radical polymerization (ATRP), were hydrolyzed to produce the acrylic acid (AAc)-containing “comb-like” graft copolymers of P(NVK-co-VBC)-comb-P(DMAEMA-co-AAc). The amphiphilic copolymers possess a fluorescent hydrophobic P(NVK-co-VBC) backbone and pH-sensitive hydrophilic P(DMAEMA-co-AAc) side chains. Arising from acid–base interaction of the hydrophilic side chains, the copolymers can self-assemble into pH-responsive fluorescent and multi-walled hollow vesicles of well-defined morphology in aqueous media. The size and layered wall thickness of the vesicles are also dependent on the length of the copolymer side chains, while the number of wall layers is dependent on the concentration of the vesicles in the aqueous media. In comparison, a N-isopropylacrylamide (NIPAAm)-containing comb-like amphiphilic copolymer (P(NVK-co-VBC)-comb-P(NIPAAm-co-DMAEMA)) of similar structure, albeit with non-interacting hydropholic side chains, self-assembles only into temperature and pH-responsive single-shelled hollow nanoparticles in aqueous media.

NEXAFS Depth Profiling of Surface Segregation in Block Copolymer Thin Films

NEXAFS spectroscopy was used to probe the surface composition and under-water surface reconstruction of thin films of comb-like diblock copolymers with cylindrical and spherical microphases. The polymers consisted of a polystyrene block, and a second block prepared from a styrenic monomer grafted with fluoroalkyl-tagged poly(ethylene glycol) side chains. Compositional depth profiling of the microphase separated block copolymer films, in the top 1−3 nm of the film, was performed to understand the role of block copolymer microstructure and self-assembly on surface composition. Using experimentally determined concentration profiles, the surface concentration of phenyl ring carbon atoms was quantified and compared with those of homopolymer and random copolymer controls. The carbon atoms from the relatively high surface energy phenyl groups were depleted or excluded from the surface, in favor of the low surface-energy fluoroalkyl groups. While it is expected that block copolymer surfaces will be completely covered by a wetting lamellar layer of the lower surface energy block, a significant amount of the higher surface energy polystyrene block was found to be present in the surface region of the cylinder-forming block copolymer. Evidently, the spontaneous formation of the cylindrical polystyrene microdomains in the near-surface region compensated for the lowering of the free energy that could have been achieved by completely covering the surfaces with a lamellar layer of the lower surface energy fluorinated block. All surfaces underwent molecular reconstruction after immersion in water. The experimental concentration depth profiles indicated an increased surface depletion of phenyl ring carbon atoms in the water-immersed thin films, due to the tendency of hydrophilic PEG side groups to be present at the polymer−water interface. Such a detailed characterization of the outermost layers of the block copolymer surfaces was possible because of the exceptional depth resolution of the NEXAFS depth profiling technique.

Synthesis of novel amphiphilic graft copolymers composed of poly(ethylene oxide) as backbone and polylactide as side chains

A well-defined amphiphilic comb-like copolymer of poly(ethylene oxide)(PEO) as main chain and polylactide (PLA) as side chain was successfully prepared via a combination of anionic polymerization and coordination-insertion ring-opening polymerization. The anionic copolymerization of ethylene oxide (EO) and ethoxyethyl glycidyl ether (EEGE) was carried out using potassium 2-(2-methoxyethoxy)ethoxide as initiator, and then ethoxyethyl groups of EEGE units of the copolymers obtained were removed by hydrolysis. Two copolymers of methoxypoly(ethylene oxide-co-glycidol) [mpoly(EO-co-Gly)] were formed with multiple hydroxyl sites (the molar ratio values of Gly to EO in copolymers: 1/10.6 and 1/5.2; Mn: 10,100 and 5,020 respectively), and them were used further to initiate the ring-opening polymerization of lactide in the presence of stannous octoate, and a well-defined comb-like copolymer of PEO as main chain and PLA as side chain was obtained. The intermediate and final products of PEO-g-PLA were characterized by GPC and NMR in detail.

Self-Assembly of Poly(4-methylstyrene)-g-poly(methacrylic acid) Graft Copolymer in Selective Solvents for Grafts: Scattering and Molecular Dynamics Simulation Study

Poly(4-methylstyrene)-g-poly(methacrylic acid) (P4MS-g-PMAA) graft copolymer was synthesized by the grafting-onto method from poly(4-methylstyrene), selectively brominated on methyl groups, and "living" poly(tert-butyl methacrylate). The average degree of polymerization of the backbone and the grafts and the average number of grafts per backbone were 251, 21, and 25, respectively. The self-assembly of P4MS-g-PMAA was studied in methanol and aqueous buffers (selective solvents for grafts). Micelles of P4MS-g-PMAA in methanol were studied by a combination of static and dynamic light scattering, TEM and SAXS. It was found that their spherical core/shell morphology resembles that of diblock copolymer micelles but they have a very low aggregation number (approximately 3) and a high cmc (approximately 0.8 mg/mL). The spherical core-shell structure revealed by SAXS was confirmed by the molecular dynamics study emulating an associate of comblike copolymers with structural parameters close to those of the experimentally studied system. Because P4MS-g-PMAA was not directly soluble in water, its aqueous solutions had to be prepared by dialysis of the methanolic solutions. In aqueous solutions, unlike in methanol, small P4MS-g-PMAA micelles (approximately 20 nm in diameter) form large secondary aggregates (approximately 100-400 nm).

Kinetics of styrene miniemulsion polymerization using poly[(stearyl methacrylate- co-( N, N-dimethylamino)ethyl methacrylate] as surfactant

Two comb-like amphiphilic copolymers have been prepared via conventional free-radical random copolymerization of stearyl methacrylate (SMA) and 2-( N, N-dimethylamino)ethyl methacrylate (DMAEMA) with different feed ratios. The resultant copolymers, poly(SMA- co-DMAEMA), were then characterized by 1H NMR and gel permeation chromatography (GPC) measurements. The surface activity of these copolymers in aqueous solution with different pH values was studied by surface tension measurements. Finally, these amphiphilic cationic copolymers were used as polymeric surfactants in the miniemulsion polymerization of styrene. The hydrophobic stearyl side chains of SMA could be strongly adsorbed onto the monomer droplets or propagating particles during the miniemulsion polymerization, while the hydrophilic and protonated PDMAEMA units at low pH media could stabilize the latexes. Moreover, the influences of the composition and amounts of the polymeric surfactants on the kinetics of the miniemulsion polymerization and colloidal stability have been investigated. The reaction rate of miniemulsion polymerization was found to increase with increasing amounts of polymeric surfactants and decrease with the increase of pH values of aqueous solution.

Nanocomposite proton conducting membranes based on amphiphilic PVDF graft copolymer

A novel comb-like amphiphilic graft copolymer of poly(vinylidene fluoride-co-chlorotrifluoroethylene)-graft-poly(4-styrene sulfonic acid-co-trimethoxysilyl propyl methacrylate), i.e. P(VDF-co-CTFE)-g-P(SSA-co-TMSPMA) was synthesized using an atom transfer radical polymerization (ATRP) technique. Successful synthesis and a microphase-separated structure of the copolymer were confirmed by proton nuclear magnetic resonance (1H NMR), FTIR spectroscopy and transmission electron microscopy (TEM). This graft copolymer was combined with tetraethoxysilane (TEOS) under acidic conditions to produce organic-inorganic nanocomposite membranes through an in-situ sol-gel reaction between TEOS and PTMSPMA, as characterized by X-ray diffraction (XRD) and TEM. Upon the introduction of silica, the proton conductivity and water uptake of the membranes decreased slightly but the thermal and mechanical properties of the membranes were enhanced significantly. Various morphologies of the nanocomposite membranes were obtained after controlling the TEOS concentration, which were correlated with the thermal, mechanical and transport properties.

Sol-gel transition behavior of amphiphilic comb-like poly[(PEG-b-PLGA)acrylate] block copolymers

The effects of comb-like amphiphilic block copolymer architectures on the physical properties such as sol-gel transition and micellization behaviors with the change of temperature and pH were examined. Comb-like poly((poly(ethylene glycol)-b-(poly(lactic acid-co-glycolic acid))acrylate-co-acrylic acid) (poly((PEG-b-PLGA)A-co-AA)) copolymers were synthesized by coupling of poly(acrylic acid) (PAA) with two different kinds of PEG-b-PLGA diblock copolymers to investigate the effects of the number of branches and hydrophilicity/hydrophobicity on the sol-gel transition and micellization. The molecular weights and chemical structures were confirmed by GPC and 1H NMR. The number of PEG-b-PLGA branches was gradually deviated from the feed molar ratio with increasing the molecular weight and the number of branches and due to the bulkiness of PEG-b-PLGA. Poly[(PEG-b-PLGA)A-co-AA] aqueous solutions showed thermosensitive sol-gel transition behavior, and the gelation took place at lower concentration with increasing the number of branches and PLGA chain length due to the increase of hydrophobicity. The temperature, at which abrupt increase of viscosity by dynamic rheometer appeared, was also in good agreement with sol-gel transition by tube-titling method. The CMC, calculated from UV-Visible spectroscopy using DPH as hydrophobic dye, also decreased with increasing the number of PEG-b-PLGA branches and PLGA chain length with same reason. The micelle size was increased with increasing temperature at the initial stage, however, decreased with further increase of temperature, since the micelles were, first, aggregated by hydrophobic intermolecular interaction, and then fragmented by dehydration of PEG segments with increasing temperature. PH-sensitive PAA backbone played a key role in physical properties. With decreasing pH, sol-to-gel transition temperature, CMC values, and micelle size were decreased because of the increase of hydrophobicity resulting form non-ionized acrylic acid. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1287–1297, 2010

Shape memory behavior of poly(methyl methacrylate)-graft-poly(ethylene glycol) copolymers

This paper describes a shape memory behavior of graft copolymers poly(methyl methacrylate)-graft-poly(ethylene glycol) (PMMA-g-PEG). In shape memory test, the sample was deformed from its original shape to a temporary shape above glass transition temperature ( T g), cooled below T g to fix the temporary shape, and subsequently heated above T g for spontaneous recovery to the original shape. By grafting PEG onto PMMA backbone, shape memory ability was drastically enhanced than PMMA homopolymer. The shape recovery ratio was decreased with the increase in the shape deformation temperature. With considering a good miscibility of backbone and side chain in PMMA-g-PEG, this shape memory ability may be related to a physically cross-linked network structure by chain entanglement of the comb-like graft copolymer. Stress relaxation measurements were investigated in order to confirm the effect of the graft chains on the shape memory behavior.

Synthesis and properties of gel polymer electrolyte membranes based on novel comb-like methyl methacrylate copolymers

Based on the principle of molecular design, three comb-like methyl methacrylate copolymer matrixes for gel polymer electrolyte (GPE) were designed and synthesized by reacting methyl methacrylate-maleic anhydride copolymer (P(MMA-MAh)) with poly(ethylene glycol) monomethyl ether (PEGME) of different molecular weight (350, 600, and 750) respectively. The structures of comb-like polymers were characterized by Fourier transform infrared (FTIR) and 1H-nuclear magnetic resonance ( 1H NMR), and their thermal properties were investigated with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The membranes of P(MMA-MAh) copolymer and comb-like copolymer based polymer electrolytes, plasticized with propylene carbonate (PC) and LiClO 4 as salt, have been prepared by solution casting technique respectively. And AC impedance was used to characterize the ion conductivity of GPE systems. Compared with P(MMA-MAh) copolymer, introducing the flexible ether chain segments can reduce the resistance of ion transport in polymer matrix and improve the mobility of electroactive ions in the GPE systems. With the increase in side chain length of copolymers, ionic conductivity of GPEs is improved dramatically. The highest conductivity observed in MMA/MAh-g-PEGME600 GPE system (matrix content: 45 wt%) is 1.22 × 10 −3 S/cm at 60 °C. And temperature dependence of GPE membranes could be described by Vogel–Tamman–Fulcher (VTF) behavior. TGA curves showed that these gel polymer electrolyte membranes possessed favorable thermal stability for lithium ion battery use.

Mechanical and swelling characterization of poly( N-isopropyl acrylamide -co- methoxy poly(ethylene glycol) methacrylate) sol–gels

The dimensional stability and rheological properties of a series of comb-like copolymers of N-isopropyl acrylamide (NIPAAm) and methoxy poly(ethylene glycol) methacrylate (mPEGMA), poly(NIPAAm–co-mPEGMA), with varying poly(ethylene glycol) (PEG) graft densities and molecular weights were studied. The thermoresponsive character of the copolymer solutions was investigated by kinetic and equilibrium swelling, as well as by static and dynamic mechanical analysis. Surface response mapping was employed to target particular compositions and concentrations with excellent dimensional stability and a relatively large change in dynamic mechanical properties upon thermoreversible gelation. The mechanical characteristics of the gels depended strongly upon concentration of total polymer and less so upon copolymer ratio. Increased PEG graft density was shown to slow the deswelling rate and increase the equilibrium water content of the gels. Upon gelation at sol concentrations of 1–20 wt.% the materials underwent no deswelling or syneresis and maintained stable gels with a large elastic regime and high yield strain (i.e. elastic and soft but tough), even within the Pascal range of complex shear moduli. These materials are unique in that they maintained a physiologically useful lower critical solution temperature (∼33 °C), despite having a high PEG content. Copolymers with a high PEG content and low polymer fraction were conveniently transparent in the gel phase, allowing visualization of cellular activity without disrupting the microenvironment. Mesenchymal stem cells showed good viability and proliferation in three-dimensional culture within the gels, despite the lack of ligand incorporation to promote cellular interaction. Multi-component matrices can be created through simple mixing of copolymer solutions and peptide-conjugated linear polymers and proteins to produce combinatorial microenvironments with the potential for use in cell biology, tissue engineering and medical applications.

Spontaneous Fusion between the Vesicles Formed by A2n(B2)n Type Comb-Like Block Copolymers with a Semiflexible Hydrophobic Backbone

The spontaneous vesicle formation and fusion of A(2n)(B(2))(n) (n = 2-10) type comb-like block copolymers with semiflexible hydrophobic backbone are studied via dissipative particle dynamics (DPD) simulations. By systemically varying the solvent condition, we construct a phase diagram to indicate the thermodynamically stable region for vesicles. The spontaneous fusion between the vesicles is studied, whose mechanism is as follows: first, a stalk is formed between the vesicles; then, the holes appear in both vesicles near the feet of the stalk; finally, the stalk bends to circle the holes and the fusion process is completed. This fusion pathway is similar to that observed in Monte Carlo simulations and dynamic self-consistent filed theory but different from those reported in coarse-grained molecular dynamics and DPD simulations. The main reason for the difference may be attributed to the molecular structures used in different simulation techniques.

Associative Properties of Amphiphilic Statistical Polymers in Aqueous Media

A novel series of comb-like amphiphilic statistical copolymers were synthesized by polymerization of an amphiphilic macromonomer, 2-(acrylamido)-dodecanesulfonic acid (AMC12S), with 2-(acrylamido)-2-methylpropanesulfonic acid (AMPS). The association behaviors of the polymers in NaCl aqueous solution were investigated by steady-state fluorescence measurements with pyrene as a polarity probe, quasielastic light scattering techniques (QELS), and a transmission electron micrograph (TEM). It was found that the series of polymers shows a strong tendency for interpolymer association, leading to the formation of multimolecular aggregates. The critical aggregation concentration (CAC) and the micropolarity of the polymer aggregates strongly depend on AMC12S mole fraction (X). An interesting feature of the polymers is that hydrodynamic sizes of the aggregates (Rh) continuously decrease with increasing X, and the increase extent of Rh with increasing polymer concentration (C) inclines to be smaller for higher X, suggesting that the polymer aggregates become a closed type progressively with increasing X.

Synthesis and Self-Assembly Behavior of Poly(fluorenylstyrene)-block-poly(2-vinylpyridine) Block Copolymers and Their Blends with Single Wall Carbon Nanotubes (SWCNTs)

We have synthesized a series of poly[4-(9,9-dihexylfluoren-2-yl)styrene]-block-poly(2-vinylpyridine) (P(St-F1)-b-P2VP) and poly[4-di(9,9-dihexylfluoren-2-yl)styrene]-block-poly(2-vinylpyridine) (P(St-F12)-b-P2VP) comblike block copolymers and investigated their self-assembly behavior. The block composition, molecular weight, and the length of the fluorene side chain were varied to control the final morphologies. Although it was found that side chains composed by up to two fluorene units were not sufficient to induce any liquid crystalline structure, the phase diagrams of the resulting block copolymers greatly depended on fluorene content. Depending on the number of pendant fluorene units, the block volume ratio, the solvent used to cast the samples, and thermal annealing history, spherical, hexagonally packed cylinders, lamellar, gyroidal, and hexagonally perforated lamellae could be found. The resulting phase diagram, compared to the reference PS-b-P2VP system, was interpreted in terms of the conformatio...